Method and apparatus for defoaming crude oil down hole



Dec. 23, 1969 c. J. ENGLE 3,485,300

METHOD AND APPARATUS FOR DEFOAMING CRUDE OIL DOWN HOLE Filed Dec. 20,1967 i [GAS s GAS FREE OIL INVENTOR.

C. J. ENGLE ATTORNEYS United States Patent 0 3,485,300 METHOD ANDAPPARATUS FOR DEFOAMING CRUDE OIL DOWN HOLE Charles J. Engle,Bartlesville, Okla., assignor to Phillips Petroleum Company, acorporation of Delaware Filed Dec. 20, 1967, Ser. No. 692,223 Int. Cl.E211) 39/00; E211 43/24 US. Cl. 166-265 7 Claims ABSTRACT OF THEDISCLOSURE thereof. This further releases any residual gas. The oil thenaccumulates above the packer. The production tubing extends into thecollected oil and the oil is now dumped efliciently up through saidtubing.

This invention relates to defoaming crude oil down hole. In one of itsaspects it relates to improving pumpability of oil from a well bottomwhen the oil accumulating therein is foaming. In another of its aspects,the invention relates to the provision of apparatus for better pumpingfoamy oil by defoaming the same prior to pumping same from the well.

In one of its concepts the invention provides a method for defoaming oildown hole in an oil well which comprises causing said oil to travelthrough an upwardly extended heating unit placed down hole in the welljust above the oil collecting therein, the unit being adapted to receivethe oil through a packer which otherwise bars flow of oil upwardly intothe casing. Oil is then caused to overflow through the heating unit andto collect around the same and around a production tubing also extendingdown into the well. Heating of the oil causes dissolved gases such ascarbon dioxide and others to emanate from the top of the heating unitand to pass upwardly through the casing while oil flows downwardlyaround the heating unit and collects in the bottom of the well above thepacker. The production tubing is rendered operative to remove defoamedoil more efficiently from the well. In another of its concepts theinvention provides apparatus for defoaming and producing a defoamed oilv wardly extending heating unit in open communication 4 through saidpacker with the oil below the packer, a production tubing extending downthe casing to a point just above said packer and pumping means forpumping oil up through said tubing. In a further concept of theinvention there is provided an upwardly extending tubular heater whichextends sufficiently above the level of oil which can accumulate abovethe packer that oil from which substantially all gases have been as itwere boiled off in the heating unit will now pass downwardly outside theheating unit as a film for removal of any residual gases still dissolvedin the oil and to further defoam the oil.

It has been noted in the field that crude oil produced into productionwell bores sometimes is quite foamy and cannot be pumped efficientlywith the conventional bottom hole pumps. The foaming occurs usually as aresult of the release of dissolved gases e.g. CO and others.

3,485,300 Patented Dec. 23, 1969 These gases are ordinarily presentespecially when in situ combustion has been practiced and the gases areproducts of combustion. As the pressure on the oil drops from reservoirto bottom hole pressure these gases have a tendency to foam up the oil.In the case of low gravity this is oils .such as Morichal oils asencountered in Venezuela. The foaming is quite extensive and the foam isquite stable.

It is an object of this invention to provide a method for producingfoamy oil in a more eflicient manner. It is another object of thisinvention to provide a method for defoaming oil down hole in a well inwhich it is being produced. It is a further object of the invention toprovide an apparatus for defoaming oil down hole of a well in which itis being produced.

Other aspects, concepts and objects of this invention are apparent froma study of this disclosure, the drawing and the appended claims.

According to the invention, there is provided a method for defoaming andproducing foamy crude oil which comprises providing down hole in a wellproducing such oil heating Zone in which the oil can be heated, passingthe foamy oil through said zone, therein heating said oil to atemperature and for a time suflicient to substantially release gasesfrom said oil, then pumping said oil from said well.

In one embodiment of the invention there is provided down hole in thewell casing a packer positioned just above the level at which foamy oilenters into the casing. Surmounting an aperture in said packer so oilcan flow thereinto is placed a tubing which can be heated. This causesoil as it enters from the formation into the well casing to passupwardly through the heated tubing. At the top of the heated tubing,owing to increased pressure provided by expansion of the gases the gasesare substantially released from the oil. The oil overflows the top endof the heated tubing and falls back in the bottom of the well casingjust above the packer and is therefore collected and ready for pumping.The usual production tubing equipped with the usual pump extendsdownwardly into the now defoamed oil and can be used to pump thedefoamed oil to the surface.

Referring now to the drawing, 1 is a well casing, 2 is a packer acrossthe bottom of the well casing but above perforations 3 through whichfoamy oil enters from formation 4 into the very bottom end of the wellcasing. 5 is a heated tube sealingly engaging the aperture 6 in packer2. 7 is a production tubing and 8 is a pump operated by a sucker rod 9.10 are the pump valves of the usual pump.

In operation the foamy oil entering through perforations 3 passesupwardly through aperture 6 and passes still upwardly into tube 5. Theoil ultimately fills tube 5 and overflows at the top as indicated by thearrows and is collected above the packer as shown by the dotted lines.On its way upwardly through the tube the oil temperature is considerablyraised say to about 300 degrees Fahrenheit for a time of about 60seconds. This results in considerable expansion of the gas in the oilwhich then escapes at the top end of the tubing and passes upwardlythrough the casing. The now heated oil flows downwardly outside tubing5. While flowing downwardly this oil can additionally release gastherefrom if any remains therein sufficient to interfere with properpumping of the same. Collected oil is pumped through valves 10 by meansof pump 8 and sucker rod 9 outwardly through production tubing 7.

In the embodiment just described the tubular heater consists of a 10foot length of 2-inch tubings spirally wound with a Chromalox tubularelement obtainable from Edwin L. Wiegand Company of Pittsburgh. The

heater coils are shown jacketed by a metal such as copper to insure evenheating. The copper jacket can be in the form of a fluted or finned tubefor added surface. Heater energy is supplied from the surface throughReda pump type electrical cables, not shown for sake of siniplicity, andthe heater is also equipped with a thermocouple for surface monitoringof heater temperature, also not shown for sake of simplicity.

The foot length and the 2-inch tubing need not b used. If desired, alonger tube, say up to and exceeding feet and a 3-inch tubing can beused for rapid production, if desired.

Thus the heater dimensions and power requirements will depend upon therate of oil production and oil temperature required for eflicient gasstripping.

Although an electrical heater has been described a "ga fire heater canbe used to carry out this invention. At present the electrical meansappears to be simpler. Accordingly, the invention has been describedwith such a means.

The invention as noted is particularly applicable to p'roducing oil fromin situ combustion project. As the in situ combustion process progressesand the oil is heated in the reservoir, it will be possible to reducethe heat requirements in the heating zone or stripper. In such event theextended tube through which the oil flows upwardly and down around theoutside of which the oil flows downwardly as a film will provide asurface from which any gases in the oil can disengage.

Thus, according to the invention natural and in situ combustion gasesflow to the surface in the annulus between the casing and the producingtubing and the oil flows out the top of the tubular heater or itsequivalent and into the space above the packer so that a conventionalsucker rod pump or the like can lift the oil to the surface. Theinvention is a specific helpful adjunct to the pumping operation in thatthe pump is now supplied with ample oil which more readily flows intothe areas around the pump since gases, particularly the excess gaseshave been removed.

Reasonable variation and modification are possible within the scope ofthe foregoing disclosure, the drawing and the appended claims to theinvention the essence of which is that there has been provided a methodand a concomitant apparatus for down hole heating of a foamy oil andcausing said oil to release its gas so that its gas will not impede thepumping operation, the method providing down hole in the well producingsuch foamy oil the heating zone in which the oil can be heated passingthe foamy oil through said zone and therein heating said oil to atemperature and for a time sufficient to substantially release gasesfrom said oil and then pumping said oil from said well; the apparatuscomprising in combination down hole in a well casing and packer a heatedtube or equivalent surmounting said packer a distance sufficient tosuitably heat the oil to cause gases therein to develop enough pressureto disengage themselves from the oil, which can be quite viscous, theoil then flowing downwardly around said tubing or equivalent, therebeing also above said packer space for accumulation of oil and therebeing in said casing a production tubing enclosing a pump meanswherewith the pump accumulated oil from above the packer to the groundsurface.

I claim:

1. A method for producing a foamy oil from a well which comprisescausing a foamy oil which is in said well to pass from within said welldirectly through a heating zone provided down hole in said well, in saidheating zone heating said oil in said well to a temperature and for atime sufficient to substantially release gases from said oil and thenpumping said oil from said well.

2. A method according to claim 1 wherein the oil is passed through anupwardly extending heated zone and down around said zone and collectedin the well from which it is then pumped to the surface.

3. A method according to claim 2 wherein there is provided a zone in thebottom of the well which impedes flow of oil upwardly in the well, thereis provided a concentric heating zone extending a substantial distanceupwardly through said well and communicating through said firstmentioned zone upwardly through said heating zone and into the portionof the well above said first mentioned zone and pumped therefrom to thesurface of the ground.

4. A method according to claim 1 for producing a foamy oil from a wellwhich comprises accumulating said foamy oil in said well, passing saidfoamy oil upwardly through a heating zone located in said well in opencommunication with said foamy oil, discharging heated foamy oil fromsaid heating zone into a zone in said well above and maintained separatefrom said foamy oil in said zone disengaging gas from said heated foamyoil, passing said gas upward and ultimately from said well, accumulatingin said zone heated oil from which gas has now been disengaged andpumping the thus treated and accumulated oil from said well.

- 5. An apparatus comprising in combination a well casing extending intoa well in the ground, a packer across the bottom of said well casing ata point above which liquid in the ground enters into said casing thusimpeding flow of liquid accumulating in said casing upwardly throughsaid casing, and means defining a heating zone in said casing just abovesaid packing in direct open communication through said packing withliquid therebelow, means above said packer in said well for pumpingliquid therefrom and from above said packer.

6. An apparatus according to claim 5 wherein the heating zone means isconstituted at least in part by an extended tubing or pipe of a lengthsufiicient to heat foamy liquid passing therethrough to a temperatureand for a time sufiicient to cause gases therein to become disengaged,said pipe extending from the packer to a level above the means forpumping to provide an upflow for heating Oll and an overflow downwardfor heated oil, thereby permitting gases disengaged from the oil duringits heating to become separated from said oil and to pass upwardly inthe well.

7. An apparatus according to claim 6 wherein the heating tube isprovided with fins on at least one surface thereof.

References Cited UNITED STATES PATENTS 1,820,291 8/ 1931 Strandell 1666X 2,134,610 10/1938 Hogg 166-60 2,3 62,680 11/1944 Troupe 166602,980,184 4/1961 Reed 16639 X 3,113,622 12/1963 Carpenter l66-39 STEPHENI NOVOSAD, Primary Examiner US. Cl. X.R. 16660, 302, 314

